The present invention relates to a jet pumps, particularly for the operation of a vacuum brake booster of a motor vehicle.
Such jet pumps are used in a brake booster system with a vacuum brake booster to increase the vacuum in the brake booster connected with a underpressure generator. In known systems of this type, a sucking jet pump is used in a suction line leading from the brake booster to a underpressure generator, to reinforce, if needed, the suction performance of the underpressure generator. For this purpose, the underpressure generator is connected at its outlet to a feed connection piece which is located laterally with respect to the flow direction at the sucking jet pump. By the addition of the pressurized outlet air of the pressure generator to the sucking jet pump, the flow in the latter is accelerated and more vacuum is generated. In order to prevent a pressure equilibration between the underpressure generator and the volume of the brake booster, a return valve arrangement is provided between the brake booster and the sucking jet pump.
From German Patent DE 43 10 761, a jet pump is known, in which the return valve arrangement is connected in one construction unit directly to the sucking jet pump. For this purpose, the sucking jet pump is constructed as a single part with a bypass made of a synthetic material and fitted with a valve arrangement provided with a feed connection piece. If the suction performance of the sucking jet pump is to be varied, then a new construction unit must be constructed in its entirety.
The object of the present invention therefore is to propose a jet pump which can be adapted, without extensive effort, to different suction performances. Furthermore, the manufacture of the jet pump should be cost advantageous, while simultaneously preserving a high functionality.